Braking mechanism for film reelsupporting shafts



April 1 1946. F. J. WENZEL "2,398,733

BRAKING MECHANISM FOR FL ELM REEL-SUPPORTINGSHAFTS Filed May 23, 1945 Patented Ap 16, 1946 BRAKING MECHANISM FOR SUPPORTING SHAFTS FILM REEL;

Fred J. Wenzel, Chicag m Ill. 1 Application May 23, 1945, Serial N0. 595,306

lClaim. (01. 188-83) This invention relates to a braking mechanism for a motion picture film reel supporting shaft and is intended for use with film-rewinding devices, upon the reel-supporting shafts of motion picture projectors and the-like.

In the use of motion picture films it is frequently necessary to rewind the film from a feed reel onto a take-up reel so as to place the ends of the film in proper position for rerunnin It is frequently desirable, in the use of such film-rewinding devices, to vary the speed at which the-feed reel and the take-up reel will revolve during the film-rewinding operation so as to prevent the two reels from running either too fast or too slow and also to permit the film to be exam-- ined for possible breaks or tears during the filmrewinding operation.

Some attempts have been made heretofore to use braking mechanisms upon certain film-rewinding devices but these have been subject to various objections either becauseof being too complicated or too expensive to manufacture or because the parts thereof tended to work loose during the use of the film-rewinding devices with which such braking devices have been used. Moreover, such priordevices have, in general, been limited to use at the so-called dead or dummy unit of a pair of film-rewinding devices and generally required that they be locked in effective or braking position.

, An object of the present invention is to pro-, vide a new and improved film rewinding device embodying as an integral part thereof a braking mechanism which is simple and inexpensive in construction, easy to operate, which does not require that it be locked in effective or braking position, in orderto perform the desired braking operation, which will not work loose during the rotation of the reel-supporting shaft of the filmrewinding device in conjunction with which it is employed, and which may be used upon either the dummy unit or end or the live unitor end of a pair of film-rewinding devices.

Other and further objects of the present invention will be apparent from the following description and claim and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment of the invenpresent invention and the purview of the append-1 ed claim. i i

Fig. 1 is a side elevationalyiew illustrating a pair of film-rewinding devices arranged in a typical manner in which such' film-rewinding'devices are used andillustrating a typical embodiment of the present invention associated with each of said film -rewinding devices;

' Fig. 2 is a side elevational F g; 5

Fig. 3 is an enlarged fragmentary sectional view on line 3--3 in Fig. 1;"and

Fig, 4 is a sectional detail view on line 4-4 in Fig.1. J

A preferred and typical" embodiment of the new braking mechanism for afilm-rewinding deview on line 2-2 in vice is shown in the drawing, and particularly tion and the principles thereof and what I now a consider to be the best mode in which I have contemplated applying those principles, Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desiredb those skilled in the art without departing from the commonly referred in Figs. 2, 3 and 4, wherein itis-generallyindicated at It], and is shown as being associated with each'of a pair of similar film-'rewin'ding devices I l, One of said film-'rewinding devices or units l I, namely, theone at the right hand end in Fig, 1, is commonly referred to in the art as the live end or unit and the other or left-hand unit is to as the "deador dummy end or unit. The-present invention is shown as beingassociated with each of said units but it may, if desired, be associated with or embodied in only one'of the'same. However, since the construction of the new braking device which is embodied in both of the "film-rewinding devices shown in the drawing is the same only one of the same will be described in detail hereinafter.

Each of the film-rewinding devices II is shown as being of the hand-operated type but the same may, within the scope of the-present invention, also be'of the motor-driven type, While both of the film-rewinding devices shown are of the same construction theymay be different in construction and one may be ofthe so-called dummy type, that is, without a handle or crank.

Each of the film-rewinding devices ll shown in the drawing comprises a casing l2 which is mounted upon a supporting standard i4 and each supporting standard H has a clamping jaw l5 formed thereon at its lower end so that the filmrewinding' device H may be clamped in position of use upon a work table IE, or the like, by manipulating a clamping screw I! which is carried 'either of the film rewinding devices I I.

ing portion or b ossl24 formedjinte'gral with. the housing l2 below-the bearing portion orbosslB,

as shown in Fig. 2. A crank 25 is attached to the shaft 23 and is provided with a handle portion 26."

A suitable film reel as 21 may be mounted upon each of the shafts I9, for rotation therewith, and is retained thereon by means of a latch finger. 28 one of which is pivotally mounted at 29 on each of itie shafts H! at the axially outer end of the lat 1'.

As illustrated in the drawing, a motion picture film 30 extends betweenand is adapted to b e-sc. lectively wound upon and unwound from. the reels 21 through the shaft 23, gear 22, and gear to rotate the reel-supporting shaft I9 and the reel 21 carried thereby.

As is well understood in the art, the reel 21 onto which the film is being wound will tend to acquire momentum and to run relatively fast as the film is wound thereon, and as this operation progresses it is often desirable to exert a braking action on the reel-supporting shaft I9 of the unitior de'vice lf'enwvhich the then takeup reel is mounted so as-to slow down-the speed of rotation of the then take-up reel 21. This is particularly desirable in those instances in which it is desired to examine the film 39 for possible 15' breaks or tears as the film is transferred from one reel to the other.

The partsand construction thus far described I have been known and 'used heretofore in the art of; film rewinding devices andthe present invention, as associated therewith, will now be described. v

V The present invention provides anovel braking mechanism which may be employed in conjunc- 4 tion with'the film reel-supporting shaft I9 of 1 The newrbrakingmechanism It includes an annular braking member orcollar 31 which is arranged upon and is splined upon the reel-supporting'shaftfllil by means of a key or pintfl which is mounted in and extends through an opening'in the shaft I9, as shown in Fig. 3, and which pin or key 39 has a portion which extends into a slot 49 in the collar 31 (Fig. 4). A flexible gasket 4| is preferably but not necessarily arranged upon the shaft, I9 between the annular In order to accomplish this result it is merely necessary for-the operator to rotate the knurled thumb nut 48 in a clockwise direction, as-seen in Fig. 1; This movement of the nut 48 threads the same axially inwardly on the threaded axially outer end portion 41 of the-reel-supporting shaft I9.; This. causes'the nut 48 to push inwardly on the thin metaldisc 46, thus compressing the resilient element or coil spring 44, which, in turn, bears against the braking collar 31, at the shoulder formed therein bythe annular groove 42 (Fig. 3).. This action forces the axiallyinner end of the annular braking collar 31jagainst the disc or gasket 4L and thus brakes the rotation of the shaft I9 and thereel 2.1 carried thereby.

Itwill-benotedthat when the knurled thumb nut .48 isthus rotated to compress the resilient element or. coil spring 44, and thereby exert a brakingactionron the braking collar 31, the annular flange 5.9 ofthe nut 48 slides over the outer surface of the annular braking collar 31.

When it is desired to relieve or reduce the braking'action-of the collar 31 this may be accomplished by rotating the nut 48 upon and relative to the shaft I9 in a direction opposite to that braking member or collar 31 and the adjacent end wall of thebearing boss l8.

, An annular groove42 is formed on the inner side of the annular braking member or collar31 and one end convolution 43 of an expansion coil spring 44, which is arranged upon the shaft I9, projects into the. annular groove 42in the braking collar 31. The other end convolution 45 of,

the resilient element or coil spring 44 bears againsta thin and preferably,metallic disc or Washer 46, which is arrangeduponthe reel-supporting shaft l9, as shown in Fig. 3.

As shown in-Fig. 3, the outer end portion 41 of the reel-supportingshaft'w is threaded and a knurled thumb nut 48 is threaded onto the said threaded outer endportion 41 of the reel-supporting shaft I9. The inner face 49 of the nut 48 bears againstthe thin metallic disc 46 and the nut 48 has an annular flange 59 which projects over and is slidable upon the outer surface of the annular braking collar 31.

In the use-of the new film rewinding device, and the braking-mechanism i0 embodied therein, the supporting standards I4-I5I 1 for the reels 21 may be clampedin position of use upon a work table I 6, or'other suitable supporting surface, and the reels 21'may be mounted upon their respective supporting shafts I9 in a manner which is well understood inthe art. The film 30 may then be run off one: reel andv onto the-other reel, by rotating the crank 25 and'handle 26 of one of the film-rewinding devices or units II. This movement of the crank 25 and handle 26 operates described above or, in .other words, in a clockwise direction. as seen in Fig. 1.

It will be noted that in the use of the new braking mechanism Hi all of the operating parts counterthereof, including the annular braking collar 31,

the ;coil spring. .44, thedisc 46 andthe manually. adjustablenut 48, are mounted upon and rotate as. a unit with the filmreel-supporting shaft I9 and in the same direction of rotation as the filmreel supporting shaft I9 during rotation of the latter. Hence, there is no tendency for any of such parts to become loose relative to other parts ofthe. braking mechanism due to rotation of the reel-supporting shaft l9 and no locking or latching device is necessary in order to hold the parts of the braking unit in effective or braking position. Thus one diificulty experienced in the use of prior braking mechanisms for and upon filmrewinding devices is eliminated.

Itis sometimes desirable in. the use of filmrewinding devices to. reverse. the direction of travel of the film during the film-rewinding operation so as to examine the film for breaks or tears therein or for other reasons and this may readily be done in the useof the film-rewinding devices H shown in the drawing and embodying the new braking units. During ,such usage the braking mechanisms, on the ,film-rewinding devices I I. may be adjusted as desired. I

Thenew braking mechanism In may be used in conjunction withlthe supporting shaft I9 for a film reel 21 ofa film-rewinding device for commercial 35 mm. film and, also for home use in conjunction with either 8 mm. or 16 mm. film.

Moreover, the new braking mechanism may also, if desired, be used in connection with or upon the film reel-supporting shafts of motion picture projectors, and in like or similar places or uses.

It will thus be seen from the foregoing description, considered in conjunction with the accompanying drawing, that the new braking mechanism for a film-rewinding device accomplishes its intended objects, and has the desirable advantages and characteristics, including those hereinbefore pointed out, and others which are inherent in the invention.

I claim:

In a braking mechanism for a motion picture film reel-supporting shaft, means providing a bearing support for rotatably supporting said film reel-supporting shaft, means for braking the rotation of said film reel-supporting shaft including a braking member mounted upon and rotatable with said film reel-supporting shaft and adapted to bear against said bearing support, and manually adjustable means carried by and rotatable witnsaid film reel-supporting shaft for urging said annular braking member into braking arrangement with said bearing support, said braking member having the form of an annular braking collar fastened to said film reel-supporting shaft for rotation therewith, said braking mechanism including a coil spring arranged upon said reel-supporting shaft and having its axially inner end convolution bearing against said annular braking collar, said braking mechanism including a manually adjustable nut threaded onto an axially outer end portion of said film reel-supporting shaft for compressing said coil spring between said annular braking collar and said nut so as to the said annular braking collar, and the said braking mechanism including a, flexible disc mounted upon the said film reel-supporting shaft between the said nut and the axially outer end convolution of said coil spring.

FRED J. WEN ZEL. 

